31 Partial pressure and volumeChemistry 140 Fall 2008Partial pressure and volumePtot = Pa + Pb +…Va = naRT/Ptot and Vtot = Va + Vb+…VaVtotnaRT/PtotntotRT/Ptot=nantotnantot=xaRecallPartial pressure is the pressure of a component of gas that contributes to the overall pressure.Partial volume is the volume that a gas would occupy at the total pressure in the chamber.Ratio of partial volume to total volume, or of partial pressure to total pressure is the MOLE FRACTION.PaPtotnaRT/VtotntotRT/Vtot=nantotGeneral Chemistry: Chapter 6

32 Average molar mass of ideal gas mixturesThe average molar mass is a sum of the products of the components molar fractions (xi) and masses (Mi).